Get two t-shirts, plain white or to really save money use ones that you have, maybe with a logo that you got off the web.
Anyway, buy some permanent markers and write things all over the other persons shirt. Nice things about that person, nick name(s), draw funny pictures or
each write those things on your own shirt with arrows pointing (like those silly shirts of the 70s) to the other person.
Now all you have to do is go wear them to the park, ballgame, beach, mall or anywhere.